1. Field of the Invention
The present invention relates to a silicon carbide semiconductor device, more particularly a silicon carbide semiconductor device including a silicon carbide layer having a surface covered with an insulation film.
2. Description of the Background Art
Japanese Patent Laying-Open No. 2002-261275 discloses the following contents. In a MOS (Metal Oxide Semiconductor) device, the plane of 4H type SiC with an oxide film stacked is a {03-38} plane or a plane having an off angle within 10° relative to the {03-38} plane. Accordingly, the channel mobility of the MOS device can be increased. This is probably because the density of dangling bonds per unit area of the constituent atom is high due to the SiC {0001} plane being a hexagonal close-packed plane, such that the interface state is increased to impede mobility of electrons, whereas the {03-38} plane is deviated from the hexagonal close-packed plane, such that electrons readily move. Furthermore, the reason why particularly high channel mobility is achieved at the {03-38} plane is probably due to the atomic bondings appearing at the surface relatively periodically despite being different from the close-packed plane.
Sufficiently high channel mobility may not be obtained by the method set forth above.